In aircrafts, very stringent requirements in relation to securing freight containers in aircraft loading spaces are existing. It must be ensured that the fastening means of the freight is sufficiently stable for the freight not to work itself loose due to aircraft movements, as this would result in damage to the aircraft structure.
Up to now, air cargo containers and pallets such as for example unit load devices (ULDs) have been affixed to aircraft cargo compartment floors with the use of bolts. This requires that for practical reasons during loading an additional gap between the ULD and the bolt has to be taken into account in the design. Within this play, a ULD can move freely during a flight, thus, depending on aircraft movements, said ULD time and again hits the locking devices at a particular speed v and acceleration a. These dynamic loads have to be taken up by the locking element and transferred to the aircraft structure.
Up to now the bolts and cargo compartment floors have been dimensioned purely statically without however taking into account the factor of play, i.e. the dynamic impact loads of the containers during flight manoeuvres. For this reason considerable safety is factored into the design calculations relating to the bolts so as to preclude any failure of these locking elements. The decisive factors affecting the extent of the dynamic loads are the impact velocities v that depend on the distance of the play and on the acceleration forces a, which act on the aircraft.